Exterior lighting and warning system

ABSTRACT

A vehicle may have vehicle controls that are used in steering, braking, and accelerating the vehicle. The vehicle may have sensors that gather information on vehicle speed, orientation, and position. The sensors may also gather information on relative speed between the vehicle and a following vehicle, information on risks of a collision between a vehicle and an external object, and other vehicle status information and vehicle operating environment information. Control circuitry may use light-based devices to display braking information, information on vehicle speed, the relative speed between a vehicle and a following vehicle, autonomous driving mode status information, custom brake light information or other user-selected information, or other information on vehicle status and the operating environment of a vehicle.

This application claims the benefit of and claims priority toprovisional patent application No. 62/198,045, filed Jul. 28, 2015,which is hereby incorporated by reference herein in its entirety.

BACKGROUND

This relates generally to systems that generate warnings, and, moreparticularly, warnings such as brake light warnings for vehicles.

Vehicles such as automobiles have brake lights. When a driver brakes toslow a vehicle, the brake lights are activated. The brake lights aremounted on the rear of the vehicle, so the driver a following vehiclecan be informed about the braking status of the vehicle. Some vehicleshave brake lights that flash under hard braking to warn followingvehicles.

Although existing systems for informing following vehicles of brakingstatus can be satisfactory in normal driving conditions, it would bedesirable to provide additional brake status information and additionalwarnings in many situations. It would therefore be desirable to be ableto provide improved brake lighting and warning systems.

SUMMARY

A vehicle may have vehicle controls that are used in steering, braking,and accelerating the vehicle. The vehicle may have sensors that gatherinformation on speed, orientation, position, and other vehicle operatingstatus information. The sensors may also gather information on relativespeed between the vehicle and a following vehicle, information on whenthere is a risk of a collision between the vehicle and an externalobject, road conditions, and other environmental conditions.

A vehicle may have audio output devices to create audio output,light-based devices such as devices based on one or more light-emittingdiodes to supply light output, and wireless circuitry to wirelesslytransmit warnings and other messages. Light-based devices may useedge-lit or backlit light guides, organic light-emitting diode displaypanels, liquid crystal display panels, light modulators based on liquidcrystals, and other circuitry for generating light output. The lightoutput may include large areas of a single color, may include text,icons, or other visual content, may include moving content, may includelight of multiple colors, and may include other patterns of light.

Light-based devices in a vehicle may be used to display brakinginformation, information on vehicle speed, the relative speed between avehicle and a following vehicle, autonomous driving mode statusinformation, custom brake light information or other user-selectedinformation, or other information on vehicle status and the operatingenvironment of a vehicle. This information may also be provided usingaudio output devices, wireless circuitry that transmits warningmessages, and other output devices in a vehicle.

Light-based devices may also display greetings and other information toa driver of a vehicle as the driver is approaching the vehicle from theoutside and as the driver walks around the vehicle. Sensors may trackthe location of a user who is near to the vehicle and can adjust thelight-based devices so that a greeting or other information is presentedon a portion of the vehicle that can be viewed by the user. Good-bymessages may be presented to a driver after the driver has parked thevehicle and is leaving the vicinity of the vehicle.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a portion of an illustrative vehicle inaccordance with an embodiment.

FIG. 2 is a schematic diagram of an illustrative vehicle or other systemin accordance with an embodiment.

FIG. 3 is a cross-sectional side view of an illustrative portion of avehicle with a light-based device in accordance with an embodiment.

FIG. 4 is a cross-sectional side view of an illustrative light-baseddevice having an adjustable mirror and an edge-lit light guide thatserves as a light source in accordance with an embodiment.

FIG. 5 is a cross-sectional side view of an illustrative light-baseddevice having an adjustable mirror and one or more adjustable lightemitters on a substrate such as a transparent substrate in accordancewith an embodiment.

FIG. 6 is a cross-sectional side view of an illustrative display havinga controllable translucent layer that may be illuminated by a lightprojector in accordance with an embodiment.

FIG. 7 is a cross-sectional side view of an illustrative backlit lightguide in accordance with an embodiment.

FIG. 8 is a cross-sectional side view of an illustrative light-baseddevice with an array of light-emitting diodes mounted in reflectors inaccordance with an embodiment.

FIG. 9 is a cross-sectional side view of an illustrative light-baseddevice with an array of light-emitting diodes and diffuser films inaccordance with an embodiment.

FIG. 10 is a rear view of an illustrative vehicle in a situation inwhich no braking is being applied to the vehicle in accordance with anembodiment.

FIG. 11 is a rear view of the illustrative vehicle of FIG. 10 in asituation in which a low amount of braking is being applied to thevehicle in accordance with an embodiment.

FIG. 12 is a rear view of the illustrative vehicle of FIG. 10 in asituation in which a moderate amount of braking is being applied to thevehicle of FIG. 10 in accordance with an embodiment.

FIG. 13 is a rear view of an illustrative vehicle of FIG. 10 in asituation in which a heavy amount of braking is being applied to thevehicle in accordance with an embodiment.

FIG. 14 is a diagram of an illustrative segmented light system of thetype that may be used to display braking information or otherinformation in accordance with an embodiment.

FIG. 15 is a diagram of an illustrative light system with bars ofdifferent heights in accordance with an embodiment.

FIG. 16 is a diagram of illustrative output from a light-based deviceincluding a gauge such as a speed gauge in accordance with anembodiment.

FIG. 17 is a diagram showing how a light such as a brake light or otherlight may have a stepwise-varying or continuously varying intensity inaccordance with an embodiment.

FIG. 18 is a diagram of an illustrative light with continuously variableor step-wise varying output intensity in accordance with an embodiment.

FIG. 19 is a diagram illustrating how a vehicle light may flash toprovide warning information in accordance with an embodiment.

FIG. 20 is a diagram of illustrative vehicle light output provided by alight-based device with areas that are adjusted independently inaccordance with an embodiment.

FIG. 21 is a diagram of illustrative vehicle light output from alight-based device that displays information such as warning informationin the form of icons, graphics, and/or alphanumeric characters (text) inaccordance with an embodiment.

FIG. 22 is a diagram of illustrative vehicle light output from alight-based device that displays current vehicle speed in accordancewith an embodiment.

FIG. 23 is a diagram of illustrative vehicle light output from alight-based device that displays the difference in speed between avehicle and a following vehicle in accordance with an embodiment.

FIG. 24 is a diagram of different illustrative user-selectable vehiclelight output patterns that may be associated with a customizable vehiclelight in accordance with an embodiment.

FIG. 25 is a side view of an illustrative vehicle with exterior lightingin accordance with an embodiment.

FIG. 26 is a front view of an illustrative vehicle with exteriorlighting in accordance with an embodiment.

FIG. 27 is a flow chart of illustrative steps involved in operating avehicle and associated systems while producing light-based warnings andother output in accordance with an embodiment.

DETAILED DESCRIPTION

Systems such as vehicles and other systems may have exterior lighting.Lighting systems on the exterior of a vehicle may be used to provideinformation to occupants of other vehicles, pedestrians, cyclists, otherroad users, and others outside of a vehicle. The information that isprovided may reflect vehicle status. Examples of vehicle statusinformation that may be conveyed to include vehicle speed, vehiclebraking status, whether a vehicle is being driven autonomously ormanually, whether a vehicle is about to exit a highway at a particularexit or is about to make a turn onto a nearby road, the followingdistance and closing speed of a following vehicle, and informationregarding potential hazards (e.g., whether a pedestrian is too close toa moving vehicle, etc.). The information that is provided using theexterior lighting systems may also include information on the operatingenvironment of a vehicle such as road hazards, weather, trafficconditions, and collision risks. If desired, vehicle status information,operating environment information, and other information may be conveyedwirelessly to nearby vehicle occupants and pedestrians. This informationmay also be provided to others using audio output or types of output.

An illustrative vehicle of the type that may be provided withinput-output devices for gathering information on vehicle status and theoperating environment of a vehicle and for providing correspondingoutput to the occupants of nearby vehicles and others is shown inFIG. 1. As shown in FIG. 1, vehicle 10 may include a body such as body12. Body 12 may have body panels and other structures that are supportedby chassis structures (e.g., body-on-frame chassis structures, unibodychassis structures, or other suitable chassis structures). Portions ofbody 12 may include doors. Interior components in vehicle 10 such asseating for a driver and other vehicle occupants may be mounted withinbody 12 and external components such as wheels 18 may be mounted to body12 (e.g., seats and wheels 18 may be coupled to chassis structures inbody 12). The structures that make up body 12 may include metalstructures, structures formed from fiber-composite materials such ascarbon-fiber materials and fiberglass, plastic, and other materials.

Windows 14 may be formed at the front and rear of vehicle 10 in openingsin body 12 and may be formed within the doors or other portions of thebody 12 of vehicle 10. As shown in FIG. 1, for example, vehicle 10 mayhave a front window such as front window 14F that faces the front ofvehicle, rearward facing windows such as rear window 14R, and sidewindows such as windows mounted within the doors of vehicle 10 (see,e.g., side windows 14D). Windows 14 may be formed from glass (e.g.,glass laminated with polymer layers), plastics such as polycarbonate, orother clear materials.

Vehicle 10 may include mirrors such as side mirrors 22. Side mirrors 22may be formed on the left and right sides of vehicle 10 and may includelight-based output devices such as light-emitting diodes. Vehicle 10 mayalso be provided with lights on the rear of vehicle 10 such as rearlights 16 (e.g., turn signal lights, brake lights, tail lights, etc.).Rear lighting may also be provided on rear window 14R and/or otherportions of the rear of vehicle 10. The rearward facing lighting ofvehicle 10 may include center high mounted stop lamps (CHMSL) such aslight 24. Light 24 may emit light through rear window 14R or may bemounted on other rear portions of vehicle 10. Additional lights invehicle 10 such as lights 20 may include headlights, turn signal lines,and fog lights. In general, lighting may be provided on any interiorand/or exterior surface of vehicle 10 such as the roof of vehicle 10,the rear window or other rear surfaces of vehicle 10, the front windowor other front surface of vehicle 10, the doors or other side surface ofvehicle 10, protruding portions of vehicle 10 such as mirrors 22 orbumpers, or any other vehicle surface. The lighting for vehicle 10(e.g., external lighting) may be provided using light-based devices(light sources) that have been mounted on the surface of vehicle 10(e.g., on body 12, inside a portion of body 12, in body 12 in anarrangement where the exterior of the light-based devices is flush withthe surface of body 12, etc.) and/or using lighting in the interior ofvehicle 10 such as lighting that that emits light through windows 14.

A schematic diagram of illustrative circuitry that may be included invehicle 10 is shown in FIG. 2. As shown in FIG. 2, vehicle 10 mayinclude control circuitry 40. Control circuitry 40 may include storageand processing circuitry for supporting the operation of vehicle 10. Thestorage and processing circuitry may include storage such as hard diskdrive storage, nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in control circuitry 40may be used to control lighting, audio devices such as speakers,wireless transmitters to transmit information to equipment external tovehicle 10, and other devices operating in vehicle 10. If desired, theprocessing circuitry in control circuitry 40 may drive vehicle 10autonomously. The processing circuitry may be based on one or moremicroprocessors, microcontrollers, digital signal processors, basebandprocessors, power management units, audio chips, application specificintegrated circuits, electronic control units, etc.

Vehicle 10 may include input-output components such as input-outputcircuitry 42. Input-output circuitry 42 allows vehicle 10 to gather dataand allows vehicle 10 to supply output data for a driver of vehicle 10,people outside of vehicle 10, and/or external or internal systems.Input-output circuitry 42 may, for example, be use to provide audio andvisual information to the driver and other occupants of vehicle 10, tothe drivers and other occupants of other vehicles such as externalvehicle 10′ (e.g., a vehicle following vehicle 10 in the roadway ordriving elsewhere in relation to vehicle 10), and to other road usersand pedestrians outside of vehicle 10. In some situations, theinformation supplied to the occupants of vehicle 10 and/or to peopleoutside of vehicle 10 may serve as a warning. For example, brake lightoutput may warn a driver of a following vehicle that vehicle 10 isslowing, a speed gauge or text (e.g., alphanumeric characters such asdigits representing speed in mph or km/hr) may inform the driver of afollowing vehicle of the current speed of vehicle 10 or the relativespeed between a vehicle and the following vehicle, and text or otheroutput may inform people near to an autonomously driven vehicle that thevehicle is operating autonomously (e.g., output may inform people thatvehicle 10 is autonomously turning, accelerating, stopping, etc.). Inother situations, audio and visual information (e.g., visual informationon the exterior of vehicle 10, etc.) may be provided that serves as agreeting, a good-by message, an advertisement or other commercialmessage, reminders (e.g., “check tire pressure”), or a public serviceannouncement. User-customized text messages, icons, audio clips, andother customized media output may be supplied using the audio and visualoutput capabilities of vehicle 10.

Input-output circuitry 42 may include sensors 30 for gatheringinformation on the operating environment of vehicle 10. Sensors 30 mayinclude light-based sensors, wireless sensors such as radar sensors,light detection and ranging (lidar) sensors, ultrasonic sensors,proximity sensors, range-finding sensors based on light, acoustics,radio-frequency signals, or other signals, ambient light sensors thatmeasure that amount of light on the exterior of vehicle 10 and/or theinterior of vehicle 10, cameras (e.g., stereoscopic cameras or othercamera systems that operate at visible wavelengths and/or infraredwavelengths and that include digital image sensors), strain gauges,parking sensors, cruise control sensors, accelerometers, touch sensors,magnetic sensors such as electronic compass sensors for determiningvehicle orientation, temperature sensors, rain sensors and othermoisture sensors, force sensors, pressure sensors (e.g., altimeters),parking brake sensors, trunk position sensors, tire pressure sensors,door position sensors, seatbelt sensors, speedometers, odometers,satellite navigation system sensors (e.g., Global Positioning Systemcircuitry for determining vehicle location, speed, and heading), andother components for making measurements on the operating environmentfor vehicle 10. If desired, sensors 30 may be used to detect thepositions, headings, and speeds of objects that are external to vehicle10 relative to vehicle 10. For example, sensors 30 may detect howrapidly a following vehicle is closing in on the rear of vehicle 10 ormay detect how rapidly a pedestrian is approaching vehicle 10 due tomovement of vehicle 10 and/or movement of the pedestrian. Sensors 30 mayalso detect a risk of potential collisions with external objects such aswhen vehicle 10 is about to strike a road obstruction that has moved infront of vehicle 10 while vehicle 10 is moving at high speed. Sensors 30may track the movement of the driver of vehicle 10 before the driver hasentered vehicle 10 and/or after the driver has exited vehicle 10. Forexample, sensors 30 may track movement of the driver as the driver walksaround vehicle 10.

As shown in FIG. 2, input-output circuitry 42 may include userinput-output devices 46. Devices 46 may be used to gather input fromusers (e.g., a driver or passenger of vehicle 10) and may be used inproviding output to users of vehicle 10 and others. Devices 46 mayinclude buttons, joysticks, steering wheels, shift levels and/orbuttons, foot-actuated controllers (e.g., a throttle pedal, a brakepedal, a clutch pedal, etc.), turn signal levers, windshield wipercontrols, and other stalk controls, steering wheel buttons and othersteering wheel controls, touch pads, keypads, keyboards, motion sensors,microphones, cameras, and other devices for gathering user input.Input-output circuitry 42 may also include circuitry for generatingaudio output such as speakers, tone generators, and vibrators (see,e.g., audio output devices 36).

Light-based devices 32 may be used to generate visible output.Light-based devices 32 may include displays (e.g., light sources witharrays of individually controlled pixels such as liquid crystaldisplays, organic light-emitting diode displays, projector displays,etc.), status indicator lights, and gauges to display navigation systeminformation, media system information, vehicle status information, andother information in the interior of vehicle 10. Light-based devices 32may include external lighting for providing light-based output outsideof vehicle 10 (e.g., displays that emit light externally and/or otherlight sources that emit light in exterior areas of vehicle 10). Ingeneral, light-based devices 32 may include any suitable light sourcesthat produce light in response to applied electrical signals such aslamps, light-emitting diodes, plasma display panel pixels, illuminatedstatus indicators, displays, lasers, arrays of light sources, individuallight sources, backlight units for displays, backlit or edge-lit lightguides, light sources that emit one or more beams of light (e.g., alaser beam, light-emitting diode beam, or a beam associated with anothercollimated light source), light sources that emit light in a fixedpattern of one or more beams, light sources that emit light using rasterscanning techniques, light sources that emit steerable beams (e.g.,light sources with mirror arrays to steer light in a light projectorsystem, light sources with one or more steerable mirrors, steerablelasers and light-emitting diodes, etc.), image projecting systems andother light projectors, light guide panels that contain light extractionfeatures that cause the light guide panels to emit light in variouspatterns, and other electrically controlled light sources.

Light-based devices (light sources) 32 may, if desired, include lightmodulators. Light modulators in devices 32 may include mechanical and/orelectrical modulators such as mechanical shutters, liquid crystalmodulators (e.g., liquid crystal shutters having polarizers), adjustablemirrors or other modulators based on cholesteric liquid crystals,modulators that change between translucent and transparent modes (e.g.,polymer-dispersed liquid crystal devices), or other structures thatexhibit opaque (light scattering) and transparent modes, guest-hostliquid crystal modulators, electrochromic modulators, light modulatorsbased on electrically bleached and/or photo-bleached photochromiclayers, and other light modulators. The light modulators may be used inmodulating some or all of the light produced by a light source (e.g., bymodulating light from one or more light-emitting diodes) and/or may beused to block stray light or otherwise adjust the appearance andperformance of light sources and other devices in vehicle 10. Ifdesired, the light modulators may be used to adjust the appearance andperformance of light sources to hide the light sources or alter theappearance of the light sources so that the light sources blend into thebody of vehicle 10 (e.g., to generate a uniform appearance).

Light-based devices 32 may contain individually controlled areas. Theseareas may be relatively small areas that serve as pixels in an array ofpixels for a display-type output device (e.g., a display integrated intoa dash-mounted navigation and media system or an external portion ofvehicle 10). Light-based devices 32 may also include components thatinclude one or only a few larger individually controlled areas (e.g.,one or more areas of about 1-100 cm², 10-1000 cm², 100-1,000,000 cm²,more than 1000 cm², less than 500 cm², etc.). For example, light-baseddevices 32 may contain light-producing devices that produce a singleblock of light over entire windows 14 in vehicle 10 or other large areasof vehicle 10. Individually controlled areas may be used to displayfixed icons or other shapes, adjustable (e.g., customizable) icons orother shapes, fixed text (e.g., “stopping” to indicate the vehicle 10 isstopping, “road hazard ahead” to indicate that dangerous road conditionsare in the road ahead, “fog ahead” to indicate that there is fog in theroad ahead, “22 mph” to indicate that vehicle 10 is travelling at 22mph, “closing speed is 22 mph” to indicate that a vehicle followingvehicle 10 is closing in on vehicle 10 at a relative speed of 22 mph,etc.), customizable text, time-varying text, scrolling text, blinkingtext, and/or output of other shapes. The light output produced bylight-based devices 32 may have multiple adjustable attributes (e.g.,color, shape, intensity, duration, location, etc.) and any set of one ormore of these attributes may be used in conveying information to aviewer.

Wireless circuitry 48 may include radio-frequency transceiver circuitryand antennas for transmitting and receiving wireless signals. Thesignals may include, for example, short-range signals such as wirelesslocal area network signals (WiFi® and Bluetooth® signals) and long-rangesignals (e.g., cellular telephone signals and other signals atfrequencies of 700 MHz to 2700 MHz and/or other suitable frequencies).Wireless circuitry 48 may be used to communicate with nearby vehicles,sensors and beacons embedded along a roadway, satellites, cellulartelephone networks, cellular telephones, wristwatches, and otherwireless devices. The wireless devices with which wireless circuitry 48communicates may be associated with a driver and passengers in vehicle10, passengers in other vehicles, pedestrians, other road users, orother people external to vehicle 10. The wireless information that istransmitted and/or received by vehicle 10 using circuitry 48 may includewarnings, vehicle occupant status information, vehicle statusinformation for vehicle 10 or other vehicles such as vehicle 10′ (e.g.,orientation, position, speed, acceleration/deceleration, brake statusinformation such as information on whether or not brakes are currentlybeing applied, throttle status, autonomous driving mode information,etc.), or information on the operating environment of vehicle 10.Operating environment information for vehicle 10 may include trafficinformation, weather information, temperature information, roadcondition information (as measured by sensors in vehicles and/orexternal sensors), information on the location, speed, and heading ofpedestrians, information on the position of nearby objects, informationon the positions of exits on highways, road locations, and other mapinformation, safety alerts, broadcast messages, vehicle-to-vehiclewireless data informing vehicle 10 of the current and future operationsof nearby vehicles, etc.

Vehicle controls 42 may include control circuitry, actuators, and othersystems for controlling vehicle operation. Vehicle controls 42 mayinclude systems for steering, braking (manual brakes, emergency brakes,power-assisted brakes, drum brakes, disc brakes, regenerative brakesthat use drive motors or other systems to recover energy and convert thekinetic energy of vehicle 10 into electrical energy stored in capacitorsand/or batteries or that use other techniques for storing recoveredenergy, or other braking systems), accelerating (e.g., motors), shiftinggears, adjusting interior and exterior lights, adjusting media systemfunctions, controlling satellite navigation system operation, adjustingairbags, seatbelts, and other safety devices, controlling audio output,controlling electronic windows, door locks, the opening and closing ofdoors and hatches, windshield wipers, defrosters, and other climatecontrols, and systems for controlling and adjusting other operationsduring the operating of vehicle 10. Vehicle controls 42 may be operatedmanually (e.g., based on input from input-devices 46) and/or may beoperated autonomously (e.g., using commands from control circuitry 40during operations in an autonomous driving mode or a safety overridemode).

Using information from sensors 30, user input from devices 46 and otherinput from devices 42, and/or information received wirelessly fromremote sources via wireless circuitry 48, control circuitry 40 ofvehicle 10 may take suitable actions. Actions that may be taken byvehicle 10 in response to information from sensors 30, user input andother input, and/or wirelessly received information include transmittingwireless information (e.g., to electronic equipment such as equipment invehicle 10′, personal electronic devices in vehicle 10′ or elsewhere,etc.), using vehicle controls 48 and other systems to autonomously driveor otherwise operate vehicle 10, issuing alerts (e.g., warningsassociated with braking, vehicle direction changes, vehicle speed, andother vehicle conditions), issuing warnings on road hazards, weatherconditions, traffic, and other operating environment information,displaying greetings and good-by messages as a driver approaches vehicle10 or leaves vehicle 10, displaying advertisements and other commercialmessages, and providing other output. Output may be supplied visually(e.g., by generating light-based output using light-based devices 32),may be supplied audibly (e.g., using audio output devices 36 to issue atone, synthesized voice, prerecorded message, or other audible output),or may be supplied using other techniques.

Light-based devices 32 may be based on light-emitting diodes, or othersources of light. In some configurations, light-based devices 32 may beformed from light-emitting diodes or other light sources mountedadjacent to curved mirrors within clear plastic housings or othermounting structures (e.g., when forming headlights, etc.). If desired,light-based devices 32 may also have thin planar shapes (e.g., whenlight-based devices 32 are being mounted to windows 14 or overrelatively large surface areas on body 12 of vehicle 10). For example,light-based devices 32 may include flexible or rigid light-emittingpanels formed from edge-lit light guide films, organic light-emittingdiode substrates, backlit liquid crystal displays, or other planar lightsources. Light-based devices 32 (e.g., light-emitting panels or otherlight sources) may be opaque or transparent. Opaque structuresassociated with light-based devices 32 may be used on portions ofvehicle 10 such as opaque portions of body 12 or on portions of windows14 that can be obscured without interfering with the fields of view ofthe occupants of vehicle 10. Transparent light-based devices 32 may beplaced on transparent portions of vehicle 10 such as portions of windows14. When not emitting light, transparent devices will not block theviews of the occupants of vehicle 10.

FIGS. 3-9 are side views of illustrative light-based devices 32. In theillustrative configuration of FIG. 3, light-based device 32 has one ormore adjustable light regions 60. Each region 60 may be individuallycontrolled to adjust the intensity of emitted light 62 from that region.Each region 60 may contain a separate light source (e.g., alight-emitting diode formed from a semiconductor die, a thin-filmlight-emitting diode such as an organic light-emitting diode, anindividually adjustable light-emitting region such as a backlit liquidcrystal display region, or other light source region). Device 32 of FIG.3 may be opaque or transparent and may be mounted on a support structurethat is opaque or transparent (see, e.g., support structure 64). Device32 may, if desired, have a planar configuration.

Device 32 may include one or more transparent glass or polymer layers.For example, an array of organic light-emitting diodes may be formed ona clear polymer substrate. In configurations such as these, device 32may be transparent. Device 32 may be mounted on a portion of vehicle 10such as vehicle structure 64. Structure 64 may be an opaque structure ora transparent structure. As an example, structure 64 may be atransparent structure such as a portion of windows 14. In this type ofarrangement, light 66 may pass through structure 64 and through device32, as shown in FIG. 3. This may allow a driver or other occupant ofvehicle 10 to look out of vehicle 10 through device 32 (e.g., through awindow on which device 32 is mounted and through device 32). Device 32may be mounted on the inside or outside of a window, may be embeddedwithin a window, may be mounted on an opaque body surface, or may bemounted elsewhere in vehicle 10.

If desired, an adjustable light modulating structure such as anelectrically controllable mirror or other light modulator may beincluded in device 32. In the example of FIG. 4, light-emitting device32 is an edge-lit light guide that has been covered with an electricallycontrollable mirror such as mirror 78. Mirror 78 may receive controlsignals from control circuitry 40 on input 80. When placed in atransparent state, an occupant of vehicle 10 may see through mirror 78,device 32, and structure 64 (i.e., in a configuration in which structure64 is transparent). When placed in a reflective state, mirror 78 willreflect light that is emitted from device 32. For example, mirror 78 mayensure that light from device 32 is directed outwardly through structure64 (e.g., a window of vehicle 10) rather than being directed into theinterior of vehicle 10. If desired, mirror 78 may exhibit mirror-likereflections only in a narrow wavelength band so that mirror 78 remainstransparent to most visible light in its reflective state.

Device 32 may contain one or more light-emitting diodes. Light-emittingdiodes such as light-emitting diode 70 of FIG. 4 may emit light 72 thatis coupled into one or more of the edges of light guide panel 74. Lightguide panel 74 may be formed from clear plastic panel, a thin flexiblesheet of plastic (e.g., a plastic film), a glass structure, a layer ofother transparent material, portions of window 14, or other suitablelight guide that guides light 72 that has been emitted fromlight-emitting diode 70. Light may be guided in panel 74 in accordancewith the principal of total internal reflection. Light extractionfeatures may be formed in light guide 74 that direct light 72 outwardlyfrom light guide 74 as illustrated by extracted light 76. The lightextraction features formed from surface irregularities, microbubbles,particles embedded within light guide panel 74, and/or other structuresthat direct light. The light extraction features may be patterned toform icons, text, large or small pixels, or light-emitting areas withother shapes. The area covered by the light extraction features may besmall or may be large so that relatively large areas of light may beproduced using a modest number of light-emitting diodes 70 (as anexample). The operation of light-emitting diodes 70 may be controlled bycontrol circuitry 40.

When light-emitting diodes 70 are turned off, mirror 78 may be placed inits transparent state so that device 32 and mirror 78 do not blocklight. When light-emitting diodes 70 are turned on, mirror 78 may beplaced in its reflective state to ensure that emitted light 76 fromdevice 32 is only directed in desired directions (i.e., throughstructure 64 in the example of FIG. 4). Mirror 78 may exhibitreflectance in a broad band (e.g., over all visible wavelengths) so thatmirror 78 is essentially opaque in its mirror state or may exhibitreflectance in only a particular narrow region of the visible lightspectrum so that mirror 78 remains transparent in its reflective state.For example, if emitted light 76 from device 32 is red (e.g., to formbrake light illumination), mirror 78 may be configured to exhibit amirror-like behavior only in a narrow portion of the visible spectrumthat overlaps the red light wavelengths associated with light 76. Mirror78 may be a cholesteric liquid crystal modulator or other suitableelectrically controllable mirror. If desired, light may be selectivelyblocked using a light modulator panel that transitions betweentransparent and non-reflective opaque states. The use of a mirror-likelight modulator such as a cholesteric liquid crystal modulator thatselectively reflects red light is merely illustrative.

If desired, light modulators (e.g., mirror 78 or other suitableelectrically adjustable light modulators) may be used to selectivelyreflect or otherwise modulate the light that has been emitted from othertypes of light-based devices. In the example of FIG. 5, device 32 is atransparent organic light-emitting diode device or other transparentlight source that emits light from one or more regions 60. Each region60 may, for example, include a respective light-emitting diode. Mirror78 may be used to direct emitted light 62 through transparent vehiclestructure 64 (e.g., a portion of windows 14) when device 32 is in useand may be placed in a transparent mode when it is desired to maximizelight transmission through device 32 and mirror 78 when device 32 is notin use.

FIG. 6 is a side view of an illustrative light-based device that isbased on a projector. As shown in FIG. 6, light-based device 32 maycontain light projector 82. Light projector 82 may emit light 84. Light84 may include one or more individually controllable areas. Anelectrically controllable light diffuser such as light diffuser 86 maybe mounted in the path of light 84 (e.g., on a vehicle structure 64 suchas a transparent vehicle structure). Diffuser 86 may be a polymerdispersed liquid crystal panel or other structure that can exhibittransparent and translucent states. Control circuitry 40 may issuecontrol signals to panel 86 on path 88. When placed in its transparentstate, panel 86 and structure 64 may be transparent and will not block avehicle occupant's view through structure 64 (e.g., through windows 14).Projector 82 may be off when panel 86 is transparent. When projector 82is turned on, panel 86 may be placed in its translucent (lightdiffusing) state, which allows light 84 to be projected onto panel 86.The light scattered from panel 86 may then be viewed by an occupant of avehicle following vehicle 10 or other people outside of vehicle 10.

Light-based devices and light modulator structures such as devices 32,78, and 86 of FIGS. 3, 4, 5, and 6 may be formed on interior surfaces ofvehicle structure 64, on exterior surfaces of vehicle structure 64, maybe embedded within a window or other vehicle structure 64 (e.g., aportion of body 12), or may be mounted in other suitable configurations.Light may be emitted in large areas (e.g., to form a single-area brakelight), may be emitted in patterns (e.g., to form icons and/or text),may be emitted in pixel arrays (e.g., to produce customizable text,icons, and/or other types of customized and/or variable output), or maybe emitted using any other suitable arrangements. The example of FIGS.3, 4, 5, and 6 are merely illustrative.

FIG. 7 is a cross-sectional side view of an illustrative configurationfor light-based device 32 based on a back-lit light guide. As shown inFIG. 7, device 32 may contain one or more light-emitting diodes 90(e.g., an array of individually controllable light-emitting diodes orone or more light-emitting diodes 90 that are operated in unison).Light-emitting diodes 90 may be mounted on a support structure such asheat sink 92. Back-lit light guide 94 (e.g., a light guide formed frommolded transparent plastic or other suitable light guiding structures)may be used to distribute light from light-emitting diodes 90 torespective portions of diffuser layer 96 (e.g., without forming gapsbetween respective portions). When light-emitting diodes 90 are turnedon, diffuse light 98 may be emitted from the exposed surface oflight-diffusing film 96.

In the illustrative example of FIG. 8, light-based device 32 has one ormore light-emitting diodes 90 mounted within one or more respectivemirrors 100 (e.g., curved mirrors) on heat sink 92. Lenticular foil 102may have downwardly facing reflective ridges that help homogenize lightfrom light-emitting diodes 90. During operation, device 32 may emitlight 98 that has been produced by light-emitting diodes 90 and that hasbeen directed outwardly through openings in foil 102 by mirrorstructures 100 and light homogenizing structures such as foil 102.

FIG. 9 is a cross-sectional side view of light-based device 32 in anarrangement in which light 98 from light-emitting diodes on heat sink 92is directed upwardly through one or more diffusing layers 96 by mirrors90.

Colors may be imparted to light-emitting diodes in regions 60,light-emitting diodes 70, light-emitting diodes in projector 82, and/orlight-emitting diodes 90 in devices 32 of the type shown in FIGS. 7, 8,and 9 using color filters, organic emissive material of desired colors,gratings, colored mirrors or diffusing layers, photoluminescentmaterials, or other suitable structures that impart emitted light fromdevices 32 with desired colors.

During operation of vehicle 10, a driver may press a brake pedal orsupply other input with devices 46. Control circuitry 40 may detect thisuser input or other input from input-output circuitry 42 (e.g., sensorinputs, wireless signals associated with vehicle-to-vehiclecommunications, etc.). Control circuitry 40 may then process thereceived data from the user and/or other sources and can take suitableactions. As an example, control circuitry 40 may issue a wirelessmessage, may create an audible alert or other audio output, and/or mayemit light that is viewable by an occupant of vehicle 10 using devices32.

In some situations, control circuitry 40 may detect braking input orother input for which brake light output or other output on the rear ofvehicle 10 is appropriate. Brake light output may be displayed using asingle set of rear brake lights, may be displayed using a pair ofrear-mounted brake lights on the left and right sides of vehicle 10 incombination with a higher brake light in the center of the rear ofvehicle 10 (sometimes referred to as a center mounted high stop light),and/or may be displayed using one or more additional brake light regions(e.g., horizontal and/or vertical strips, portions of windows 14, etc.).Brake light output may be displayed in an analog fashion, so thatincreases in braking input or other appropriate input results incorrespondingly more brake light output and/or may be displayed in astepwise fashion (e.g., so that predetermined amounts of brake lightoutput are not provided until a brake pedal input or other input hasexceeded a given threshold). If desired, brake light output may beaccompanied by other forms of braking indicator output such as audiobrake indicator output, wireless messages indicative of vehicle braking,or other braking indicator output from input-output circuitry 42. Theuse of control circuitry 40 to produce brake light output in response todriver braking or other data is merely illustrative.

To enhance safety, it may be desirable to provide output from vehicle 10(e.g., braking light output or other output) in multiple levels (e.g.,in a stepwise output arrangement). When the need for a warning is lowest(e.g., when a driver is not applying brakes), the output from vehicle 10may be lowest (e.g., no brake lights may be illuminated, no audio outputmay be generated, and/or no wireless alerts may be generated). When theneed for a warning is highest (e.g., in an emergency situation in whicha driver is braking hard to avoid an accident), vehicle 10 may supplyoutput from vehicle 10 in an elevated fashion (e.g., by producing arelatively large amount of braking light output or by otherwiseenhancing the ability of a driver of a following vehicle or othersoutside of vehicle 10 to detect the output). In intermediate situations(e.g., in non-emergency situations in which the driver of vehicle 10 isbraking a moderate amount), corresponding intermediate level(s) ofwarning may be produced (e.g., braking light may be supplied by vehicle10 at one or more intermediate levels).

Consider, as an example, the illustrative scenario of FIGS. 10, 11, 12,and 13. In this example, vehicle 10 has brake lighting formed fromlight-based devices 32 in multiple different regions on the rear ofvehicle 10 such as region 100-1 (e.g., a center mounted high stop lightposition), region 100-2 (a rear brake light position on body 12), region100-3 (a horizontal strip running across some or all of the rear of body12), and region 100-4 (some or all of the portion of rear window 14Rthat is not covered by center mounted high stop light 110-1). Theselocations of these regions and/or the patterns of light emitted in theseregions may be customized by a driver or other user of vehicle 10 bysupplying control circuitry 40 with text, images, graphics, voice input,menu selections, or other user input via input-output devices 46. Forexample, a user of vehicle 10 may select from a menu of pre-approvedbrake light patterns for the rear of vehicle 10 in region 110-3 and/orother regions.

Vehicle 10 of FIGS. 10, 11, 12, and 13 is shown in four differentillustrative braking scenarios. In the scenario of FIG. 10, vehicle 10is being driven normally and the driver of vehicle 10 is not pressing onthe brake pedal of vehicle 10. Because no brake light warning forfollowing vehicles is needed in this situation, none of the brake lightregions on the rear of vehicle 10 have been activated (i.e., thelight-based devices 32 in regions 110-1, 110-2, 110-3, and 110-4 ofvehicle 10 of FIG. 1 are all off).

In the scenario of FIG. 11, the driver of vehicle 10 is pressing lightlyon the brake pedal of vehicle 10. As a result, more of the brake lightregions on the rear of vehicle 10 have been lit. In particular,light-based devices 32 in regions 110-2 and 110-1 have been activated,so that regions 110-1 and 110-2 are illuminated and are producing brakelight for the vehicle following vehicle 10. Brake light illumination maybe red or other suitable color that complies with brake lightingregulations.

In the scenario of FIG. 12, the driver of vehicle 10 is braking morestrongly than in the scenario of FIG. 11. In response to detecting thishigher level of braking, control circuitry 40 illuminates more brakelight regions such as horizontal strip region 100-3 of FIG. 12.

An emergency braking scenario is illustrated in FIG. 13. When controlcircuitry 40 detects heavy braking, control circuitry 40 can turn on allbrake light regions on the rear of vehicle 10. In the FIG. 13 scenario,brake light region 110-4 has been illuminated in addition to previouslyilluminated brake light regions 110-1, 110-2, and 110-3.

The presence of increasing levels of brake light illumination on therear of vehicle 10 helps accurately inform the drivers of followingvehicles of the current braking status of vehicle 10. Becauseinformation on a variety of different braking levels is conveyed, thelikelihood that these drivers will overreact or underreact to changes inthe braking status of vehicle 10 is reduced.

In the example of FIGS. 10, 11, 12, and 13, one or more additional brakelight areas were illuminated as progressively higher levels of brakingwere detected (e.g., as control circuitry 40 detected that the brakepedal in vehicle 10 was respectively pressed by less than a firstthreshold, by more than the first threshold, by more than a secondthreshold, and by more than a third threshold). If desired, the outputof one or more of the light-based devices 32 associated with the brakelight regions of vehicle 10 may be increased in a continuously variable(analog) manner (e.g., so that small changes up or down in the amount ofapplied brake pressure result in corresponding small changes up or downin the illumination of one or more brake light regions). Analogadjustments such as these may be used for one or the brake light regionson the rear of vehicle 10, some of the brake light regions on the rearof vehicle 10, or on all brake light regions.

In addition to or instead of varying brake light intensity in an analogand/or binary fashion, other brake light attributes may be varied bycontrolling light-based devices 32. Examples of brake light attributesthat may be varied include: brake light color, brake light duration(e.g., blinking period), the content of a brake light pattern (e.g., thepresence or absence of ancillary warnings such as text warnings or iconwarnings), the location and/or number of brake light regions that areilluminated within a predetermined region, the content of a text warningmessage or other text message, brake light illumination blinkingpatterns (e.g., the order in which multiple different brake lightregions are illuminated in sequence), etc. Braking status may also beconveyed by sending wireless messages (e.g., to inform the occupants ofnearby vehicles of braking status), and/or by issuing audible alerts.Wireless messages may be sent to other vehicles such as vehicle 10′(e.g., a following vehicle) using vehicle-to-vehicle communicationsand/or may be conveyed to the cellular telephone, wristwatch, or otherwireless device associated with pedestrians or others outside of vehicle10.

FIG. 14 shows illustrative brake light output that may be provided usinga segmented brake light region. Brake light region 110R includesmultiple individually controllable subregions 110R′. Regions 110R′ maybe illuminated in a pattern that is responsive to the amount of brakingof vehicle 10 that is detected by control circuitry 40 (e.g., using abrake pedal sensor). If no braking is detected, light-based devices 32in regions 100R′ may be turned off. If hard braking is detected, all ofregions 110-R′ in region 110R may be illuminated. In the scenario ofFIG. 14, an intermediate level of braking has been detected, so two ofregions 110R′ (i.e., regions 112) have been illuminated. In the exampleof FIG. 15, regions 110R′ have progressively increasing size, whichhelps visually convey the relative importance of each region whenbraking status information is being displayed.

In addition to displaying brake light information on the rear of vehicle10, it may be desirable to display associated information such asvehicle speed, the relative speed between a vehicle following vehicle 10and vehicle 10 (sometimes referred to as a closing speed), or otherinformation related to the status of vehicle 10. If desired, vehiclespeed or relative vehicle speed may be displayed textually. In theexample of FIG. 16, vehicle light region 110 on the rear of vehicle 10has the shape of a gauge (e.g., a speedometer). The speed of vehicle 10or the relative speed between a following vehicle and vehicle 10 may bedisplayed by arm 116 of the gauge. Arrangements of the type shown inFIGS. 14, 15, and 16 may be used in displaying vehicle speed, closingspeed, position information, and/or other information (e.g., informationin addition to or instead of braking information).

As illustrated in FIG. 17, a vehicle lighting area (e.g., area 114) maybe illuminated with progressively varying amounts of light (e.g., lowlight amount 114A, moderate light amount 114B, and large light amount114C). Light output and/or other output characteristics may be varied ina stepwise fashion and/or in an analog fashion.

The lighting regions on vehicle 10 associated with light-based devices32 may have any suitable pattern. FIG. 18 shows an illustrative solidpattern in which a single light-based device 32 has illuminatedrectangular area 120. The intensity of the illumination of area 120 maybe adjusted to convey brake status information or other information. Inthe example of FIG. 19, lighting region 122 alternates (blinks) betweenan unilluminated state (state 122A) and an illuminated state (state122B). FIG. 20 shows an illustrative lighting region (region 124) thathas multiple strip-shaped areas 124-1, 124-2, 124-3, 124-4, and 124-5.These areas may be illuminated in sequence as with segmented region 110Rof FIG. 14, may be turned on and off in different patterns, may use achasing lights pattern, may flash at one or more different frequencies,may have one or more different colors and/or intensities, and/or may useother illumination schemes to convey information. The example of FIG. 21shows how a lighting region for vehicle 10 such as region 126 mayinclude icons and/or text. Text (e.g., alphanumeric characters) maycontain static text information (e.g., “stopping” to indicate thatvehicle 10 is stopping) or may contain information that is continuouslyupdated (e.g., “current speed is 22 mph”). Non-vehicular information mayalso be displayed (e.g., “tornadoes in area,” “fog ahead on roadway,”“traffic congestion in 1 mile,” etc.). Icons in region 126 may includewarning symbols (e.g., warning triangles, icons that include warninginformation within triangular boundaries, etc.). Text, graphics, video,and/or other information in a lighting region on vehicle 10 may be usedto display vehicle status information such as the current speed ofvehicle 10 (see, e.g., region 128 of FIG. 22) and/or the relative speedbetween vehicle 10 and a vehicle following vehicle 10 as determined bysensors 18 such as a lidar sensor, ultrasonic sensor, camera,speedometer, and/or other sensors that determine the speed of vehicle 10and the relative speed of the following vehicle (see, e.g., region 130of FIG. 23). If desired, warning information and/or other informationmay be displayed as a function of vehicle closing speed (relativespeed), vehicle heading information, vehicle position, weather, othervehicle status and operating environment information, etc.

Areas such as area 114 of FIG. 17, region 110R of FIG. 15, a gauge-typeindicator pattern such as brake light gauge 110R of FIG. 16, regionssuch as regions 110-1, 110-2, 110-3, 110-4, region 120 of FIG. 18,region 122 of FIG. 19, region 124 of FIG. 20, and regions 126, 128, and130 of FIGS. 21, 22, and 23, and other regions illuminated bylight-based devices 32 in vehicle 10 may be formed on the rear ofvehicle 10, on the sides of vehicle 10, on the roof of vehicle 10, onthe front of vehicle 10, on windows 14, on body 12, on wheels 18, and/oron other portions of vehicle 10. These areas may be provided with text,solid patterns of light, light with adjustable colors, light that isdisplayed with a particular timing (e.g., flashing, etc.), light thathas a stepwise varying intensity, light that has a continuously varyingintensity, or other light-based output to convey information to viewersof vehicle 10. The light-based output may be accompanied by sound output(tones, synthesized and/or pre-recorded voice, etc.) and/or wirelesslyconveyed information (e.g., messages to vehicles, portable electronicdevices, and other recipients with wireless receivers).

Lighting regions may be used to convey information on braking status(e.g., whether or not brakes have been applied and, if so, how stronglythey have been applied) or other vehicle status information (e.g.,driving mode—autonomous or manual, vehicle speed, vehicle orientation,vehicle position, etc.), upcoming vehicle navigation information (e.g.,whether vehicle 10 is about to exit the highway as determined bynavigation system information in vehicle 10 or other data source),whether vehicle 10 has detected a pedestrian or other obstacle in itspath and is about to stop, whether the control circuitry of vehicle 10is predicting that vehicle 10 will potentially be struck by anothervehicle or is subject to other collision risks, whether vehicle 10 isexecuting a stop, turn, acceleration-related maneuver, or otherprocedure, etc.

If desired, the lighting regions displayed on vehicle 10 may becustomized by a driver or other user of vehicle 10. For example, controlcircuitry 40 may use input-output circuitry 42 to present the driver orother user with a selectable on-screen menu option or other selectableoption (e.g., a voice command option, an option presented on anaccessory device such as a cellular telephone or wristwatch that iswirelessly linked to vehicle 10, etc.) so that the user can selectbetween different lighting schemes for a given lighting region. As anexample, a user may be presented with an opportunity to select betweenthe patterns of FIG. 24 (e.g., a square pattern such as region 132, astop-sign shaped pattern such as region 134, and flame-shaped patternsuch as region 136).

Once chosen, a selected pattern may be presented by light-based device32. As an example, a pattern selected from the illustrative patternchoices of FIG. 24 may be displayed in a region such as region 112-2 orother region on the rear of vehicle 10 to serve as customized brakelights. Users can supply control circuitry 40 with customized text,customized icons, images that serve as output, custom colors, or othersuitable customized patterns. The available options from which users canchoose may satisfy applicable regulations on vehicle lighting. Ifdesired, satellite navigation system information, user-suppliedgeographic information, or other location information may be used bycontrol circuitry 40 to determine the current regulatory environment inwhich vehicle 10 is operating. Control circuitry 40 may then switch to acompliant output light pattern (e.g., a default pattern or anappropriate user-selected pattern) in the event that a givenuser-selected pattern becomes non-compliant as a user travels betweendifferent jurisdictions.

If desired, vehicle exterior lighting may extend in a horizontal bandaround one or more sides of vehicle 10 or may otherwise be provided onthe sides of vehicle 10. As shown in FIGS. 25 and 26, for example,lighting region 140 may extend along the sides of body 12 and across thefront of body 12 (and, if desired, along the rear of body 12 asillustrated by lighting region 110-3 of FIG. 10). Lighting region 140may contain light of varying intensity, flashing light, light of one ormore colors, text, icons, or other information. As an example, lightingregion 140 may display one type of information (color, text, icon,intensity, font, etc.) when vehicle 10 is being operated manually andmay be display another type of information when vehicle 10 is beingoperated autonomously by control circuitry 40. In this way, people inthe vicinity of vehicle 10 may be informed when vehicle 10 is operatingautonomously.

Text, icons, or other information in region 140 may convey warnings topedestrians, following vehicles, and others outside of vehicle 10.Examples of information that may be conveyed includes messages such as“stopping,” “driving autonomously,” “about to turn right,”“accelerating,” “slippery road,” “stay in crosswalk,” etc. Greetings andgood-by messages may be displayed. For example, sensors 30 may detectwhen a driver of vehicle 10 is approaching vehicle 10 from the outsideof vehicle 10 and can display a greeting on light-based devices. Sensors30 can track the location of the driver or other user of vehicle 10 asthe user walks around vehicle 10 and can adjust the location of thedisplayed information accordingly. Good-by messages may be displayed toa driver as the driver leaves the vicinity of vehicle 10. Commercialinformation (e.g., advertisements), public service announcements,reminders, messages associated with incoming emails, voice mails, andtext messages (e.g., “you have three new messages”), other notifications(e.g., “wiper fluid is low—fill up before you drive”), and other contentmay be displayed on the exterior of vehicle 10 using light-based devices32. Warnings and other information may be generated as a result of userinput to vehicle input devices such as input to a brake pedal,accelerator, steering wheel, or other input device, may be generatedbased on sensor input (e.g., lidar, cameras, and other object-detectionsensors), may be based on navigation system information (e.g.,information that reveals where vehicle 10 is driving autonomously or isbeing driven under manual control), may be based on wirelessly receivedvehicle-to-vehicle communications, may be based on other wireless data,or may be based on other information about vehicle status and theoperating environment of vehicle 10.

Illustrative steps involved in operating vehicle 10 are shown in FIG.27. At step 150, control circuitry 40 may gather information from adriver or other user of vehicle 10 (e.g., user input through a userinput interface associated with selection of a custom lighting schemefor exterior vehicle lighting such as brake lighting or other lighting),may gather information from sensors 18 (e.g., brake sensors, acceleratorpedal sensors, steering wheel sensors, sensors associated with othervehicle control input devices that receive user input, sensors thatmeasure the external environment around vehicle 10 such as lidarsensors, cameras, etc., and other sensors 18), and may gatherinformation from wireless sources such as other vehicles 10′, remoteportable equipment (cellular telephones, wristwatch devices, etc.),satellite navigation system satellites, wireless road infrastructure,and other data sources.

At step 152, the sensor data and other data may be processed. Forexample, control circuitry 40 may determine how strongly a driver isapplying a brake pedal, may determine how much a driver is accelerating,may determine the orientation, speed, and position of vehicle 10, maydetermine the relative speed between vehicle 10 and a following vehicle(e.g., vehicle 10′) may determine the orientations, speeds, andlocations of pedestrians and others outside of the body of vehicle 10,cyclists, and other vehicles relative to vehicle 10, may determinewhether vehicle 10 is about to turn, whether there is risk that vehicle10 will collide with an object (e.g., whether vehicle 10 is on acollision course with another vehicle), whether vehicle 10 has beenswitched into or out of autonomous mode, whether vehicle 10 is about tostop, may determine whether pedestrians or others outside of vehicle 10are in the path of vehicle 10, may track the location(s) of one or morepeople outside of vehicle 10 (e.g., a driver who is approaching vehicle10 and or who is departing vehicle 10 after a drive) and may make otherdeterminations on the current status of vehicle 10, the predictedbehavior of vehicle 10, the movement and position of vehicle 10 relativeto other vehicles and pedestrians, weather and road conditions, themovement of people in the vicinity of vehicle 10, and other informationon vehicle status and the operating environment for vehicle 10.Information on incoming wireless messages and other status informationmay also be gathered.

At step 154, the determinations of step 152 may be used by controlcircuitry 40 in generating warnings and other output (e.g., text and/oricons that serve as greetings, good-by messages, status information,notifications, reminders, advertisements, public service announcements,etc). The output may be supplied to the occupants of vehicle 10 and tothe occupants of other vehicles, pedestrians, cyclists, people walkingaround vehicle 10 (whose locations can be tracked using sensors 30 suchas cameras, radar, lidar, proximity sensors, etc.) and others outside ofvehicle 10. Output may be supplied wirelessly (e.g., in the form ofmessages to personal electronic devices associated with messagerecipients), may be supplied audibly (e.g., by issuing an alert usingspeakers in vehicle 10), and/or may be issued using light emitted fromlight-based devices 32. Light-based devices 32 may emit light from therear of vehicle 10 (e.g., light in one or more brake light regions) ormay emit light from the roof, front, sides, or wheels of vehicle 10).The light that is emitted may be emitted in a stepwise fashion (e.g.,with increasing numbers of light-emitting regions such as increasingnumbers of brake light regions being added with increasing braking orother activity and/or with a stepwise increase in emitted lightintensity or other output characteristics), may be emitted in an analogfashion (e.g., so that each variation in brake intensity or other changeresults in a corresponding variation in light-based output), and/or mayinvolve other visual changes (changes in color, pattern, light duration,text content, icon content, etc.). Visible output from light-baseddevices 32 may be used to provide information on the status of thebrakes of vehicle 10 and the operation of other vehicle controls,potential collision risks (e.g., collision risks related to differencesin speed between vehicle 10 and other vehicles and/or distances betweenvehicle 10 and other vehicles, collision risks due to the projected pathof vehicle 10 and the locations and trajectories of objects near to thisprojected path, etc.), information on the intended route of vehicle 10,autonomous mode status information, greetings, advertisements,notifications, reminders, information about incoming message status,public service announcements, and other information produced during theprocessing operations of step 152. As an example, when vehicle 10detects that a person has arrived in the vicinity of vehicle 10, textfor a greeting message may be displayed on a portion of light-baseddevices 32 that is visible to the detected person. As indicated by line156, operations may loop back to step 150 after step 152 (i.e., datagathering, data processing, and output generation operations may beperformed continuously).

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A vehicle system for a vehicle that is beingdriven by a driver, wherein the vehicle is being followed by a followingvehicle, the system comprising: control circuitry; at least one sensorwith which the control circuitry determines a relative speed between thevehicle and the following vehicle; and a light-based device that emitslight, wherein the control circuitry adjusts the light-based device inresponse to the relative speed, wherein the control circuitry directsthe light-based device to display information on the relative speed, andwherein the control circuitry directs the light-based device to displayalphanumeric characters representing the relative speed.
 2. The vehiclesystem defined in claim 1 wherein the light-based device compriseslight-emitting diodes.
 3. The vehicle system defined in claim 1 furthercomprising wireless circuitry, wherein the control circuitry transmitsinformation wirelessly with the wireless circuitry based on the sensordata.
 4. The vehicle system defined in claim 1 wherein the vehicle has arear, the vehicle system further comprising a brake sensor that detectshow strongly the driver is braking the vehicle, wherein the light-baseddevice comprises one of a plurality of light-based devices on the rearof the vehicle, and wherein the control circuitry adjusts thelight-based devices on the rear of the vehicle in response to howstrongly the driver is braking the vehicle.
 5. A vehicle system for avehicle that is being driven by a driver, wherein the vehicle is beingfollowed by a following vehicle, the system comprising: controlcircuitry; at least one sensor with which the control circuitrydetermines a relative speed between the vehicle and the followingvehicle; and a light-based device that emits light, wherein the controlcircuitry adjusts the light-based device in response to the relativespeed, wherein the control circuitry directs the light-based device todisplay information on the relative speed, wherein the control circuitryprocesses data from the at least one sensor to determine when there is arisk of a collision between the vehicle and an object, and wherein thecontrol circuitry takes action in response to detecting the risk of thecollision.
 6. The vehicle system defined in claim 5 wherein the actiontaken by the control circuitry comprises emitting light with thelight-based device.
 7. The vehicle system defined in claim 5 furthercomprising an audio output device, wherein the action taken by thecontrol circuitry comprises producing an audible output with the audiooutput device.
 8. A vehicle system for a vehicle that is being driven ata speed, the system comprising: at least one sensor that measures thespeed at which the vehicle is being driven; a light-based device thatemits light representing the speed; control circuitry that processessensor data from the sensor and that adjusts the light-based device inresponse to the speed; at least one additional sensor with which thecontrol circuitry measures braking of the vehicle by the driver; and atleast four additional light-based devices that the control circuitryprogressively illuminates in response to detection of correspondingprogressively increasing amounts of measured braking, wherein at leastone of the additional four light-based devices is a transparent devicethat overlaps a window in the vehicle and displays an icon.
 9. A vehiclesystem for a vehicle that is being driven at a speed, the systemcomprising: at least one sensor that measures the speed at which thevehicle is being driven; a light-based device that emits lightrepresenting the speed; control circuitry that processes sensor datafrom the sensor and that adjusts the light-based device in response tothe speed; vehicle controls that control steering, acceleration, andbraking for the vehicle; and an additional light-based device that emitslight, wherein the control circuitry operates in an autonomous mode inwhich the control circuitry autonomously drives the vehicle using thevehicle controls, and wherein the control circuitry adjusts theadditional light-based device in response to operating the vehicle inthe autonomous mode.
 10. The vehicle system defined in claim 9 whereinthe control circuitry directs the additional light-based device todisplay a given text message in response to operating in the autonomousmode.
 11. The vehicle system defined in claim 10 wherein the textmessage is a warning message and wherein the control circuitry displaysthe warning message in response to a change in vehicle status.
 12. Thevehicle system defined in claim 11 wherein the change in vehicle statusis a decrease in vehicle speed and wherein the warning message comprisesalphanumeric characters displayed on the additional light-based device.13. The vehicle defined in claim 12 further comprising a body having afront, rear, and sides and wherein the additional light-based deviceprovides illumination for the vehicle in a lighting region that extendsin a horizontal strip across at least the front of the body.
 14. Avehicle system for a vehicle that is being driven at a speed, the systemcomprising: at least one sensor that measures the speed at which thevehicle is being driven; a light-based device that emits lightrepresenting the speed; control circuitry that processes sensor datafrom the sensor and that adjusts the light-based device in response tothe speed; a body having a rear; an additional light-based device thatemits light in a brake light region on the rear; and a user input devicethat receives input from a user of the vehicle, wherein the controlcircuitry directs the brake light region to display a custom brake lightpattern in the brake light region based on the input received from theuser.
 15. The vehicle system defined in claim 14 further comprising: atleast one display that displays alphanumeric characters on the rear. 16.The vehicle system defined in claim 15 further comprising: additionalsensors that gather information on vehicle operating status, wherein thecontrol circuitry adjusts the alphanumeric characters that are displayedbased at least partly on the vehicle operating status.
 17. A vehiclesystem for a vehicle that is being driven at a speed, the systemcomprising: at least one sensor that measures the speed at which thevehicle is being driven; a light-based device that emits lightrepresenting the speed; control circuitry that processes sensor datafrom the sensor and that adjusts the light-based device in response tothe speed; a body; at least one additional sensor with which the controlcircuitry detects a person outside of the body; and an additionallight-based device that emits light at a location outside of the body,wherein the control circuitry uses the light-based device to displaytext for the person outside of the vehicle in response to detecting theperson.